The present invention relates to an arrangement for the cleaning of a filler pipe in a packing machine of the type which forms a packing material tube around the filler pipe, which tube is then filled with contents and is divided up into filled and closed packages by means of sealing jaws arranged underneath the end of the filler pipe, whereby the arrangement comprises lines and a pump for the circulation of a cleaning liquid.
The invention also relates to a method for the cleaning of a filler pipe in a packing machine with use of the abovementioned arrangement.
In the foodstuff industry the demand is made more and more often that products should be packed with the help of sterile packing processes. This applies especially to the packing of those foodstuffs which are sensitive and which present an opportune growth medium for bacteria, such as in the case of milk and cream.
A number of methods and machines have been produced to meet these demands for sterile packing processes, and among the sterile packing machines which are utilized for the packing of milk and cream there is to be found a machine of the type which converts a web of packing material which has first been sterilized to a tube whilst it passes vertically downwards through the machine. The tube is formed around a delivery pipe for the contents extending vertically through the machine and is provided with a longitudinal seal, whereupon the tube, continuing its downwards movement through the machine, is filled with the contents. At some distance underneath the end of the filler pipe a clamping together of the tube then takes place in that the tube walls are pressed together and sealed to one another in transverse zones extending over the tube. After a possible shaping phase, the tube is cut at regular intervals in the sealing zones so that packing containers separated from one another are obtained.
In the above packing machine mention is thus already made of the delivery pipe for contents, the so-called filler pipe, located inside the tube formed of sterilized packing material. Inside the tube, there is moreover a float arranged around the lower end of the filler pipe and a transfer mechanism between the float and a control valve arranged in the filler pipe, which parts, like the lower end of the filler pipe, are in direct contact with the sterile contents. These parts, in other words, must be extremely carefully cleaned.
The cleaning of the lower end of the filler pipe and the float arranged thereon takes place at present by hand-washing, which means that this part of the filler pipe is detachable and is removed for separate washing and sterilization, whereupon it is assembled again in position when production of the packing container commences. A certain risk of re-infection exists, however, in the course of the assembly work, and it has therefore been proposed that the parts should be sterilized in situ, the sterilizing agent (usually steam) being made to flow through the packing material tube. After the assembly of the washed filler pipe, the packing material tube is advanced so that it fully covers the delivery pipe, whereupon the material tube is sealed off at its lower end and the sterilizing agent is made to circulate through the delivery pipe and the packing material tube. In this method there is a great risk, however, that the hot and strong cleaning agent may penetrate through the tube wall.
It is an object of the present invention to provide a method and an arrangement which ensure an effective cleaning of the parts of the packing machine which during production come into direct contact with the contents present in the packing material tube.
It is another object of the present invention to provide a method and an arrangement which allow effective cleaning and sterilization of the parts without requiring one to dismantle them.
These and other objects have been achieved in accordance with the invention in that an arrangement for the cleaning of a filler pipe in a packing machine of the type which forms a packing material tube around the filler pipe, which tube is then filled with contents and is divided up into filled and closed packages by means of sealing jaws arranged underneath the end of the filler pipe, whereby the arrangement comprises lines and a pump for the circulation of a cleaning liquid, has been given the characteristic that the arrangement includes a cleaning container in the form of a tubular body which is surrounding the lower end of the filler pipe and has an inside diameter which is greater than the outside diameter of the packing material tube and a base which is provided with a controllable outlet line and connectable to the lower end of the tubular body in order to form, together with the tubular body, a space which surrounds the lower part of the filler pipe.
A preferred embodiment of the arrangement in accordance with the invention moreover has been given the characteristic that the tubular body is movable in relation to the filler tube and the packing material tube.
Another preferred embodiment of the arrangement in accordance with the invention moreover has been given the characteristic that the tubular body is arranged concentrically around the filler pipe and is displaceable between a lower, active position, where together with the detachable base it surrounds the lower end of the filler pipe, and an upper production position, where the packing material tube can pass without hindrance through the body.
Another preferred embodiment of the arrangement in accordance with the invention moreover has been given the characteristic that the tubular body is provided with a number of spraying nozzles pointed in the direction of the filler pipe of the packing machine which are connected via a delivery line to a pump.
The tubular part of the cleaning container is thus permanently placed in the machine, which makes possible a rapid and simple cleaning and sterilization. To ensure that it presents no hindrance during production, it can be moved to an upper position where its lower end does not interfere with the forming jaws of the machine and other elements acting upon the packing material tube.
A preferred embodiment of a method for the cleaning of a filler pipe in a packing machine with use of the abovementioned arrangement has been given the characteristic that cleaning liquid is delivered via the interior of the filler pipe as well as via nozzles in a cleaning container arranged around the lower end of the filler pipe and provided with a controllable outlet, the cleaning liquid being sprayed continuously via the nozzles in the direction of the filler pipe whilst the delivery of cleaning liquid through the filler pipe is instantaneously reduced when the level in the cleaning container exceeds a predetermined limit.
By means of the preferred method in accordance with the invention the inside of the filler pipe will be cleaned with the help of the cleaning liquid flowing through the filler pipe whilst the outside of the filler pipe as well as the float that may be arranged around the filler pipe will be cleaned partly by dipping into the cleaning liquid, partly by being directly sprayed with cleaning liquid.
In a further embodiment the method of the invention for the type of packing machines where the level of contents in the packing material tube is controlled by a valve which is actuated by a float located in the tube has been given the further characteristic that the said valve controls the delivery of cleaning liquid through the filler pipe in such a manner that during the cleaning procedure the float is displaced continuously between an upper and a lower limit position.
This means that when the outlet from the cleaning container is suitably adjusted the liquid level in the cleaning tank will successively increase and diminish, the float being displaced between its limit positions so that even the part of the filler pipe which is normally covered by the float will be exposed to liquid spraying.
In a further embodiment the method in accordance with the invention is characterized in that during the cleaning procedure the outlet is alternatingly opened and closed so as to achieve the desired level variations in the cleaning container. This makes for a more rapid level variation in the cleaning container and thus for a more effective cleaning .